Metallic culvert.



LLLLLLLLLLLLLL T. .APPLIC AAAAAAAAAAAAAAAAAAA `enla rged',.of the same. Fig. 3 is a section on i 1n`+w .of`Fig. 2. Fig. 4 is an end view smooththroughout its length.

' section is greater'than semcylindrical, and

-'lower,` both being of the usual corrugated UNITEI) STATES PATENT OFFICE.

KARL JOHAN THORSBY, OF OAKLAND, CALIFORNIA, ASSIGNOR TO CALIFORNIA COR- RUGATED CULVERT COMPANY, OF OAKLAND, CALIFORNIA, A CORPORATION.

METALLIC CULVERT.

To all whom it may concern:

Be it known that I, KARL J OHAN THORSBY, a subject of the King of Norway, residing at Oakland, in the county of Alameda i and State of California, have invented certain new and useful Improvements in Metallic Culverts, of which the following is a specification.

My invention relates to that classof culverts composed of metallic Sections, adapted, for convenience in transportation, to be nested, and provided with means for forming a joint at their meeting edges when the Sections are fitted together to form the complete culvert or pipe.

My invention consists in the novel joint between the Sections, and it has for its obj ect the provision of a joint with a relatively extensive bearing surface, of great strength, and smooth inner surface, the joint being economical in manufacture, and easily established in installation.

' Referring to the accompanying drawingsz- Eigure 1 is a erspective view of my culvert; Fig. 2 is a fragmentary side* view,

of the culvert.

' 1 is the upper metallic section and 2 is the type; j Thelower section is semicylindrical and itsterminal surface on each sde is left The upper its terminal portions are cut upward the distance of its excess' of circumference to form separated lugs 3, which are oft'set outward as shown, a distance of twicethe thick-' ness of the plate, the`material between said lugs being left as strai ht tongues 4. When the upper section is p aced upon the lower section, the ofiset lugs 3,0verlap the outer surfaces of the lower section, while the tongues 4 pass down *upon and overlap the inner surfaces of said lower section. As shown in the drawings, and particula'ly in Fig. 3, the cutsbywhich the lugs 3 and the tongues4 are formed are approximately in the apexes of the ridges and in the bottoms of the Valleys of the corrugations, with the Specification of Letters Patent. Patented J une 27, 1911 1911. Serial No. 612,481.

`of the culvert, have one end lying-in approximately the circles of greatest interior diameter of said culvert. The shoulder formed 'by this end is, therefore, enioved to the greatest distance from the main current of the material through the culvert, and presents the least obstruction to the flow of the 'tended, so that said flowis from' right to left in said Fig. 3. Thus a smoother inner surface is presented to the flow. The joint thus formed has a relatively extensive bearing surface, and bein formed of parts which are integral wth the Sections, is strong and reliable with no tendency to Shear as would be the case if the lugs were separate pieces. Moreover, the efl'ect on the is economically practical in manufacture and is readily established in setting up the culvert.

' Having thus described my invention, what I clairn as new and desire to secure by Letters Patent is- 1. A metallic culvert comprising circumferentially corrugated Sections, the terminal surfac'es of one of said sections being a flat plane in the direction of their length, and the terminal portions of the other section bein cut circumferentially in approximate y the apexes of the ridges and the bot- -toms of the valleys of the corrugations, to form s'eparated lugs, said lugs being ofi'set, the' portions of said section between the lugs being left as straight tongues.

2. A metallic culvert comprising circumferentially corrugated complemental Sections fitted together by means of alternating ofi'set lugs and straight tongues, formed by cir- 'cumferentially directed cuts made in approximately the apexes of the ridges and the bottons of the Valleys of the corrugations.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

KARL J OHAN THORSBY.

Witnesses:

WM. F. BooTH, D. B. RICHARDS.

result that tongues 4, which lie on the'inside material when the culvert is laid, as is ininner surface is a smooth one,- which is of mportance in dranage culverts. The joint 

